Columbia University's Infectious Disease-Epidemiology Training Program was established in 2001 to support the development of researchers committed to the field of Epidemiology and Infectious Diseases. The Program, situated at the Mailman School of Public Health, catalyzed the building of a comprehensive ID-EPI course curriculum;expanded research opportunities for trainees resulting in a large number of abstracts, presentations and publications by the trainees;and led to collaborative efforts among faculty from different Centers at Columbia, including the School of Nursing, the College of Physicians and Surgeons, the Mailman School of Public Health, and from institutions outside of Columbia, such as the New York Academy of Medicine and the NYC Department of Health. The need for researchers with expertise in epidemiology has increased dramatically in the past few years and we therefore seek support for eight training positions in the ID-EPI Training Program (two additional pre-doctoral and 2 additional post-doctoral positions). The proposed program will build and expand on the success of the ongoing program, with an expanded menu of courses, a large number of experienced mentors and research opportunities. New areas of focus will include: community epidemiology which is important in the study of racial/ethnic disparities in disease burden;healthcare-associated infections which has become one of the most serious and costly problems within healthcare;molecular epidemiology, an area that incorporates sophisticated molecular techniques into the study of disease patterns;and medical informatics, a reflection of the rapidly advancing fields of computing and communications and their application to healthcare and epidemiology. Trainees will be selected based on their prior experience/expertise and their interest and commitment to infectious diseases epidemiology. Intensive recruitment efforts will be made to continue to enroll and retain trainees from under-represented groups. Pre-doctoral trainees will pursue a PhD degree program. Post-doctoral trainees, who will typically have completed the clinical year of an infectious diseases fellowship, will pursue either MPH or MS degrees in Epidemiology. Trainees will attend courses and colloquia and receive training in ethics and appropriate research conduct. They will carry out research projects supervised by a mentor from the Training Program. The Program has a rigorous evaluation plan that includes process and outcome measures. These features of the Training Program, combined with its rich array of resources, will guide this program to the achievement of its goals.